如何将一个NodeJS二进制缓冲区转换为JavaScript数组缓冲区?
当前回答
Buffer的实例也是node.js 4中Uint8Array的实例。X和更高。因此,最有效的解决方案是直接访问缓冲区自己的.buffer属性,如https://stackoverflow.com/a/31394257/1375574。Buffer构造函数也接受一个ArrayBufferView参数,如果你需要走另一个方向。
注意,这不会创建一个副本,这意味着对任何ArrayBufferView的写入都将写入原始的Buffer实例。
In older versions, node.js has both ArrayBuffer as part of v8, but the Buffer class provides a more flexible API. In order to read or write to an ArrayBuffer, you only need to create a view and copy across.
从Buffer到ArrayBuffer:
function toArrayBuffer(buffer) {
const arrayBuffer = new ArrayBuffer(buffer.length);
const view = new Uint8Array(arrayBuffer);
for (let i = 0; i < buffer.length; ++i) {
view[i] = buffer[i];
}
return arrayBuffer;
}
从ArrayBuffer到Buffer:
function toBuffer(arrayBuffer) {
const buffer = Buffer.alloc(arrayBuffer.byteLength);
const view = new Uint8Array(arrayBuffer);
for (let i = 0; i < buffer.length; ++i) {
buffer[i] = view[i];
}
return buffer;
}
其他回答
"From ArrayBuffer to Buffer"可以这样做:
var buffer = Buffer.from( new Uint8Array(arrayBuffer) );
我已经将节点更新到5.0.0版本 我在研究这个:
function toArrayBuffer(buffer){
var array = [];
var json = buffer.toJSON();
var list = json.data
for(var key in list){
array.push(fixcode(list[key].toString(16)))
}
function fixcode(key){
if(key.length==1){
return '0'+key.toUpperCase()
}else{
return key.toUpperCase()
}
}
return array
}
我用它来检查我的vhd磁盘映像。
Buffer的实例也是node.js 4中Uint8Array的实例。X和更高。因此,最有效的解决方案是直接访问缓冲区自己的.buffer属性,如https://stackoverflow.com/a/31394257/1375574。Buffer构造函数也接受一个ArrayBufferView参数,如果你需要走另一个方向。
注意,这不会创建一个副本,这意味着对任何ArrayBufferView的写入都将写入原始的Buffer实例。
In older versions, node.js has both ArrayBuffer as part of v8, but the Buffer class provides a more flexible API. In order to read or write to an ArrayBuffer, you only need to create a view and copy across.
从Buffer到ArrayBuffer:
function toArrayBuffer(buffer) {
const arrayBuffer = new ArrayBuffer(buffer.length);
const view = new Uint8Array(arrayBuffer);
for (let i = 0; i < buffer.length; ++i) {
view[i] = buffer[i];
}
return arrayBuffer;
}
从ArrayBuffer到Buffer:
function toBuffer(arrayBuffer) {
const buffer = Buffer.alloc(arrayBuffer.byteLength);
const view = new Uint8Array(arrayBuffer);
for (let i = 0; i < buffer.length; ++i) {
buffer[i] = view[i];
}
return buffer;
}
我尝试了上面的Float64Array,它只是没有工作。
我最终意识到,真正的数据需要读入正确的块视图。这意味着一次从源Buffer读取8个字节。
总之,这是我最后得到的……
var buff = new Buffer("40100000000000004014000000000000", "hex");
var ab = new ArrayBuffer(buff.length);
var view = new Float64Array(ab);
var viewIndex = 0;
for (var bufferIndex=0;bufferIndex<buff.length;bufferIndex=bufferIndex+8) {
view[viewIndex] = buff.readDoubleLE(bufferIndex);
viewIndex++;
}
可以把ArrayBuffer看作是类型化的Buffer。
因此,ArrayBuffer总是需要一个类型(所谓的“数组缓冲区视图”)。通常,数组缓冲区视图有Uint8Array或Uint16Array类型。
Renato Mangini有一篇关于ArrayBuffer和String之间转换的好文章。
我在一个代码示例中总结了基本部分(用于Node.js)。它还展示了如何在类型化的ArrayBuffer和非类型化的Buffer之间进行转换。
function stringToArrayBuffer(string) {
const arrayBuffer = new ArrayBuffer(string.length);
const arrayBufferView = new Uint8Array(arrayBuffer);
for (let i = 0; i < string.length; i++) {
arrayBufferView[i] = string.charCodeAt(i);
}
return arrayBuffer;
}
function arrayBufferToString(buffer) {
return String.fromCharCode.apply(null, new Uint8Array(buffer));
}
const helloWorld = stringToArrayBuffer('Hello, World!'); // "ArrayBuffer" (Uint8Array)
const encodedString = new Buffer(helloWorld).toString('base64'); // "string"
const decodedBuffer = Buffer.from(encodedString, 'base64'); // "Buffer"
const decodedArrayBuffer = new Uint8Array(decodedBuffer).buffer; // "ArrayBuffer" (Uint8Array)
console.log(arrayBufferToString(decodedArrayBuffer)); // prints "Hello, World!"